Dual collimated deposition apparatus and method of use

ABSTRACT

A dual collimation deposition apparatus and method are disclosed in which the dual collimation apparatus includes at least a long-throw collimator in combination with one or more physical collimators. A new physical collimator and shield design are also disclosed for improved process uniformity and increased equipment productivity.

This application is a continuation of Ser. No. 09/103,527 filed Aug. 4,1998 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to a system and method for depositing athin film of material onto a surface of an object, such as asemiconductor or thin film head substrate, and in particular to a dualcollimation system and method for depositing thin material films onto asemiconductor or a thin film head substrate.

Plasma sputtering is a physical vapor deposition (PVD) technique forthin film deposition. The process of sputtering a thin film onto anobject is well known. The sputtering process may be used to deposit athin film of material onto a plurality of different surfaces which mayinclude a magnetic media substrate, magneto-optical media substrate, asemiconductor substrate, a thin-film head substrate, a flat-paneldisplay substrate and the like. In the sputtering process, it is desiredto place a thin film of atoms of a particular type, such as a cobalt,onto the substrate. A typical sputtering apparatus may include a pieceof target material, a vacuum or low-pressure sputtering chamber, and asubstrate located on a substrate holder beneath the target material. Tocause some of the atoms or compound species from the piece of targetmaterial to deposit themselves on the substrate surface, an electricalDC, pulsed DC, AC or RF power supply is connected between the targetmaterial (typically via a bonded backing plate) and the chamber, and alow-pressure (e.g., 0.5 mTorr to 30 mTorr) inert gas (e.g., Ar) and/or areactive gas (e.g., N₂, O₂ or the like) medium is established within thechamber. When a high enough voltage is applied to the target material, aplasma is formed with the atoms being released by the target materialvia ion bombardment by the plasma ions. The gas in the chamber may havea low pressure so that a majority of the atoms from the target materialtravel from the target material onto the substrate surface withoutcolliding with any gas molecules (i.e., negligible or minimal scatteringof the sputter species). In many thin-film deposition applications, toobtain the best quality thin films, it is desirable for the atoms tostrike the surface of the substrate at a 90° angle (i.e., normalincidence) which provides a collimated stream of atoms.

In order to improve the quality of the thin film produced by thesputtering apparatus, the target may be located a greater distance fromthe substrate, which is known as a long-throw or natural sputteringapparatus. In the long-throw or natural sputtering apparatus, the atomsfrom the target material travel a longer distance so that the atoms thatare not going to strike approximately perpendicular to the surface ofthe substrate, and within a space cone with relatively narrow angulardistribution around the central normal axis, may strike the sides of thesputtering chamber. Thus, a larger percentage of the atoms or sputterspecies from the target material strike the surface of the substrateclose to a perpendicular angle within a narrow angular distribution fromthe normal axis. The long-throw sputtering apparatus has severallimitations. First, because the atoms or sputter species are traveling agreater distance to the surface of the substrate, they may strike moregas molecules due to scattering collisions and form poorer quality filmsunless the pressure of the gas in the sputtering chamber is reduced. Ifthe gas pressure is reduced too much, however, there will not besufficient gas pressure in the chamber to sustain a stable plasma.Typically, the long-throw sputtering processes require gas pressurespreferably below 1 mTorr, thus limiting the process window for thistechnique. Moreover, the long-throw sputtering systems require morestringent vacuum pumping due to larger process chamber volumes andsurface area.

Another technique to improve the quality of the thin films (i.e.,improving the total number of atoms or sputter species which strike thesurface of the substrate at a perpendicular angle or near perpendicularangles) is to place a perforated plate or a physical collimator in thechamber between the substrate and the target surface. This apparatus iscalled a physical collimation sputtering apparatus. The perforated platehas a predetermined aspect ratio (i.e., the ratio of the height of thehexagonal or circular holes in the plate to the diameter of the holes inthe plate) so that most atoms which pass through the plate will strikethe surface at approximately a right angle or within a narrow-angle conearound the perpendicular axis. Thus, the perforated plate acts as aspatial filter for the atoms or sputter species and prevents the atomsor sputter species emitted from the target material at more than somepredetermined angle (outside a predetermined cone) from striking thesurface of the substrate. The atoms or sputter species which strike theplate, but do not pass through the physical collimator holes, aredeposited on the plate or within the holes. Therefore, as the plate isbombarded by more and more atoms, the holes of the plate will graduallybecome coated and eventually plugged up and the plate must be replacedafter processing a certain number of substrates. Therefore, the totallifetime of the plate in the chamber is limited and the plate must bereplaced often which is time consuming and reduces the overall equipmentuptime. With either approach, the maximum collimation that can beachieved is limited.

Therefore, it is desirable to provide a sputtering apparatus whichprovides a more collimated stream of atoms or sputtering species whichavoids these and other problems of known devices, and it is to this endthat the present invention is directed.

SUMMARY OF THE INVENTION

In accordance with the invention, a dual collimated sputtering apparatusand method are provided which improves step coverage and bottom coveragein large aspect ratio contacts and vias in a semiconductor integratedcircuit chip, improves bottom coverage and step coverage for barriers,liners in vias, or trenches in a semiconductor device, and reducesencroachment in a lift-off patterning structure for an abutted junction(the latter used in magnetic thin-film heads). The dual collimator inaccordance with the invention may have a long-throw collimator combinedwith one or more physical collimators. The long-throw collimatorprovides some initial collimation and the subsequent one or morephysical collimators provide additional filtering of the sputtered fluxwhich enhances the overall degree of collimation. In addition, since thelong-throw collimator already ensures that some non-collimated atoms orsputtered species strike the walls (or shield walls) of the depositionchamber, the perforated plates of the physical collimator block asmaller fraction of the incoming flux (i.e., atoms) so that the overalllifetime of the perforated physical collimator is increased. The dualcollimator apparatus may also be operated at low pressures (e.g., suchas less than 2 mTorr) so that the probability of atom scattering due toa collision with background gas atoms (within the long-throw collimator)is minimized so that more collimated atoms or sputtered species strikethe surface of the substrate.

In addition, the bottom coverage for a 3:1 aspect ratio (AR)semiconductor via hole improves from about 30% using conventionalphysical collimation to as much as 50% using the dual collimationapparatus in accordance with the invention while the sidewall coverageof the via hole is not significantly affected (resulting in continuouscoverage of topological features). As compared to a sputtering processwith no collimation, dual collimation in accordance with the inventionalso reduces encroachment for lift-off structures by a factor of three.The sidewall angle of a metal layer deposited on a lift-off structurewith respect to the horizontal plane increases from 100 for nocollimation and 160 for long-throw collimation to 320 for dualcollimation in accordance with the invention (the exact sidewall anglecan be increased or decreased by changing the dual-collimationparameters).

In addition, the full width half maximum value (FWHM) of the sputteredflux incident on the wafer decreases from ±550 for no collimation and±45° for long-throw collimation to ±25° for dual collimation indicatingthat more of the flux with the dual collimator strikes the wafer atclose to a perpendicular angle. The dual collimation process inaccordance with the invention also provides a well defined abuttedjunction in which the permanent magnet contacts of, for example, amagneto-resistive (MR) sensor may be placed with minimal overlap.

For a chromium (Cr) deposition, the deposition rate decreases from 100Å/kW/min with a conventional long-throw collimator to only approximately28 ÅkW/min with the dual collimator in accordance with the invention.This decrease in the rate of deposition may be attributed to theincreased degree of collimation of the deposited atoms. In addition, aCr (30 Å)/Co₈₂Cr₆Pt₁₂ (350 Å)/Cr(1150 Å) stack processed using the dualcollimation process in accordance with the invention shows excellentmagnetic properties with a coercivity of 1630 Oe and a squareness of0.91.

To further improve the dual collimation process which increases thedeposition uniformity and increases the mean number of wafers that maybe processed between cleans (i.e., an indication of how quickly theperforated physical collimator plate becomes blocked), a novelperforated plate of a physical collimator and a new collimator shieldare disclosed.

In accordance with the invention, a physical-vapor deposition apparatusfor depositing material from a target onto a substrate is providedcomprising a deposition chamber, a target holder housed within thechamber holding a target from which a deposition flux is generated, asputtering energy source such as a DC magnetron source, a substrateholder housed within the chamber beneath the target holder, and aphysical collimator between the target holder and the substrate holderfor controlling an amount of deposition flux impinging on the substrate.The apparatus may further comprise a second collimator to provide, incombination with the physical collimator, a collimated deposition ofmaterial onto the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a diagram illustrating a conventional sputtering apparatus;

FIG. 1b is a diagram illustrating a sputtering apparatus equipped with aconventional physical collimator device;

FIG. 1c is a diagram illustrating a sputtering apparatus equipped with aconventional long-throw collimator;

FIG. 1d is a diagram illustrating a sputtering apparatus equipped with adual collimator device in accordance with the invention;

FIG. 2 is a diagram showing the process steps to fabricate an abuttedjunction (such as for a magneto-resistive or MR thin-film head) whichmay be fabricated more precisely with a dual collimation device inaccordance with the invention;

FIG. 3 is a diagram illustrating more details of the dual collimatordevice of FIG. 1d;

FIG. 4 is a diagram illustrating the full-width half-maximum (FWHM)distribution curves for the collimators shown in FIGS. 1a-1 d;

FIG. 5 is a diagram illustrating a measurement of the properties of amagnetic film deposited using the dual collimator configuration inaccordance with the invention;

FIG. 6a is a diagram illustrating various properties of the edge of afilm deposited on a lift-off structure;

FIG. 6b is a diagram illustrating an atomic force microscope scan of theedge of a film deposited on a lift-off structure fabricated with thedual collimator;

FIG. 7a is a diagram illustrating a simulation of an abutted junctionfabricated using a conventional collimator;

FIG. 7b is a diagram illustrating the abutted junction of FIG. 7afabricated using the dual collimator in accordance with the invention;

FIG. 8a is a diagram illustrating a lift-off structure fabricated usinga conventional long-throw collimator;

FIG. 8b is a diagram illustrating the lift-off structure of FIG. 8afabricated using the dual collimator in accordance with the invention;

FIG. 9a is a diagram illustrating a step structure fabricated using aconventional physical collimator;

FIG. 9b is a diagram illustrating the step structure of FIG. 9afabricated using the dual collimator in accordance with the invention;

FIGS. 10a-10 d illustrate different rotating magnetron arrays that maybe used in connection with the dual collimator;

FIG. 11 is a diagram illustrating an improved physical collimator whichis part of the dual collimator in accordance with the invention;

FIG. 12 is a chart illustrating the sheet resistance and non-uniformityfor a Cr film as a function of chuck height;

FIG. 13 is a chart illustrating the sheet resistance and non-uniformityfor a Cr film as a function of deposition pressure;

FIG. 14 is a diagram illustrating a simulated lift-off structure;

FIGS. 15A-15B are charts illustrating the FWHM value sputterdistribution and simulated deposition, respectively, when no collimationis used;

FIGS. 16A-16B are charts illustrating the FWHM value sputterdistribution and simulated deposition, respectively, when long-throwcollimation is used;

FIGS. 17A-17B are charts illustrating the FWHM value sputterdistribution and simulated deposition, respectively, for dualcollimation in accordance with the invention;

FIG. 18 is an example of dual collimator system of the invention;

FIGS. 19A-19B are charts of FWHM value for a long-throw collimator;

FIG. 20 is a chart illustrating various performance parameters of a dualcollimator in accordance with the invention;

FIG. 21 is a diagram of a first embodiment of a shield; and

FIG. 22 is a diagram of a second embodiment of a shield.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The invention is particularly applicable to a dual collimated DCmagnetron sputtering deposition apparatus. It is in this context thatthe invention will be described. It will be appreciated, however, thatthe dual collimation apparatus and method in accordance with theinvention has greater utility, such as being used with differentdeposition techniques such as RF diode sputtering, RF magnetronsputtering, ionized physical-vapor deposition (PVD), and ion beamdeposition.

Prior to describing the dual collimator apparatus in accordance with theinvention, several conventional prior art collimators will be described.FIG. 1a is a schematic diagram illustrating a conventional physicalvapor deposition (PVD) apparatus 30 that includes a vacuum orlow-pressure deposition chamber 32 having sidewalls 34, 36, a targetassembly 38 and a substrate 40 placed within the chamber beneath thetarget assembly 38. A power supply 42 may apply a voltage, such as anegative DC voltage, to the target material. As the target materialreaches a sufficiently high voltage, a plasma if produced due to theelectrical breakdown of an inert gas and atoms on the surface of thetarget material are released. In fact, a plasma is formed because thepressure of the gas (which may be argon, helium, nitrogen, etc.) withinthe chamber 32 is adjusted to ensure that a plasma is produced andmaintained. Once a plasma is established, the plasma ions bombard thetarget surface and the atoms or sputtered target species fall onto thesubstrate 40 at various incident angles. However, a good quality thinfilm is only formed when the atoms or sputtered species are normallyincident (i.e., strike the substrate normal to the surface of thesubstrate because atoms or sputtered species that do not strike thesurface at about 90° may results in voids and cause the film todelaminate or flake). An apparatus that attempts to ensure that moreatoms strike the substrate normal to the surface is known as acollimated deposition apparatus.

FIG. 1b is a schematic diagram of a conventional physically collimateddeposition apparatus 46 that includes the chamber 32, sidewalls 34, 36,the target assembly 38, the electrical power source 42, and thesubstrate 40 underneath the target assembly. The physically collimateddeposition apparatus 46 may also include a perforated plate 48 placedbetween the target material and the substrate. The plate may have aplurality of hexagonal or circular holes through it in a predeterminedpattern which block some of the atoms or sputtered species released bythe target material. In particular, the holes in the plate have aparticular height and diameter (and therefore a particular aspect ratio)so that atoms or sputter species approaching the substrate more than apredetermined number of degrees away from normal to the substrate (oroutside a predetermined spatial cone) do not pass through the platewhich improves the collimation of the atoms and improves the quality ofthe thin films being deposited. The physical collimated depositionapparatus, however, suffers from a short mean time between cleaningssince the holes in the plate become rapidly blocked by the atoms that donot pass through the holes of the plate.

FIG. 1c is a diagram of a conventional long-throw, natural collimationdeposition apparatus 50 which also improves the collimation of the atoms(i.e., more atoms strike at a normal angle to the surface of thesubstrate). The long-throw collimation apparatus also includes thechamber 32 with sidewalls 34, 36, a target assembly 38, an electricalpower source 42 and a substrate 40 underneath the target assembly. Toimprove the collimation of the atoms or sputtered species beingdeposited, the distance between the target and the substrate isincreased so that atoms which are not falling within the predeterminedangular distribution cone with respect to the normal axis to thesubstrate surface are more likely to strike the sidewalls 34, 36 of thechamber (or the corresponding chamber shields, not shown) instead of thesubstrate. The long-throw collimator PVD apparatus, however, suffersfrom several drawbacks. First, because the target is farther from thesubstrate, the atoms must travel a greater distance and therefore maystrike more gas molecules (more gas-phase scattering) which reduces thecollimation of the atoms or sputtering species. It is possible to reducethe pressure of the gas in the chamber to reduce the number of gasmolecules, but a stable plasma cannot be formed at too low of a pressure(e.g., at pressures much below 1 mTorr). Second, since atoms strike thesidewalls 34, 36, films form on the sidewalls which may chip off andcontaminate the thin film on the substrate with particles. Now a dualcollimation apparatus in accordance with the invention will bedescribed.

FIG. 1d is a dual collimated deposition apparatus 56 in accordance withthe invention. The apparatus may have a vacuum or low-pressure chamber58 with sidewalls 60, 62, a target assembly 64 and a substrate 66located underneath the target assembly 64. In accordance with theinvention, the deposition apparatus may include a long-throw depositionapparatus and one or more perforated physical collimators plates 68located between the target assembly 64 and the substrate 66. The one ormore plates may have a plurality of holes in a predetermined patternwhich blocks some of the atoms or sputtered species generated by thetarget. In accordance with the invention, the combination of the longthrow deposition apparatus with the one or more perforated platesfurther increases the collimation of the atoms, as described below. Thedual collimated deposition apparatus also increases the lifetime of theperforated plate, as described below. The theoretical results obtainedwith the conventional deposition apparatus and the dual collimator inaccordance with the invention will now be described.

Theoretical calculations show that both a 1:1 aspect ratio long-throwcollimation PVD (the aspect ratio is the ratio of the height of thecollimator to the diameter of the collimator) and a 1.5:1 aspect ratio(AR) physical collimation PVD into a via hole structure are expected toprovide similar results with a maximum incident angle (as measured fromthe wafer surface normal) of sputtered atoms of ˜30° as described below.This result assumes that there is no scattering of the sputtered speciesor atoms by the background gas during their transit to the wafer whichis a reasonable assumption for sputtering pressures below 2 mTorr in thecase of physical collimation in which the mean free path for sputteredatoms is ˜10 cm at 1 mTorr. For a 12″ long-throw collimator having a 6″substrate, a 12″ target and a 15-18″ distance between the target andsubstrate, the maximum incident angle (MIA) is Arc Tan((½ substratesize+½ target size)/Target−Substrate distance)=Arc Tan(9″/(15-18″)). Forphysical collimation, the maximum incident angle is Arc Tan(1/A.R.)=ArcTan(1/1.5). Thus, both collimators have about a 30° maximum incidentangle around the perpendicular axis.

No further improvement in collimation is expected by increasing thedistance between the target and the substrate in the long-throwcollimator since, as the distance is increased, there is a greaterlikelihood that the sputtered atoms will be scattered in their transitto the wafer by gas molecules. Slight improvement may be expected bydecreasing the sputtering pressure to reduce the number of gasmolecules, but even at 2 mTorr, the typical transit path is a factor offour longer than the mean free path for the sputtered atoms. Increasingthe physical collimator aspect ratio (i.e., the ratio of the height ofthe holes to the diameter of the holes) to 2:1 will also provide someimprovement and the maximum incident angle will decrease to about ˜25°,resulting in a sharper angular distribution of the sputtered species.

In accordance with the invention, a maximum improvement resulting in aminimum MIA is expected by combining collimation approaches (i.e. dualcollimation). For example, a long-throw collimator can be combined withone or more perforated plates of a physical collimator as shown in FIG.1d. The dual collimation apparatus in accordance with the inventionprovides the following advantages which will be described in more detailbelow. First, the dual collimator provides a sharper cutoff angle forthe sputtered atoms even though the maximum incident angle is notaffected. In particular, combining collimators reduces the full widthhalf maximum value (FWHM) of the sputtered flux at the wafer, andsignificantly reduces the flux in the wings of the distribution (i.e.flux at high incident angles) as described below with reference to FIG.3.

Second, since the sputtered atoms will lose some energy during thetransit between the long-throw collimator and the perforated plate ofthe physical collimator, the sputtered atoms which strike the physicalcollimator are more likely to stick to the surfaces of the physicalcollimator rather than scatter off of the collimator holes. Any atomsthat scatter off the collimator holes tend to reduce the degree of PVDcollimation. In addition, a sputtering gas may be introduced between thetarget (using a gas injection port on the long-throw collimator or a gasinjection ring around the target) and the physical collimator so that apressure differential can be established across the physical collimator.In this mode, a low pressure can be achieved between the physicalcollimator and the substrate, while a slightly higher pressure exists inthe vicinity of the target. This higher pressure is necessary to sustaina stable plasma while the lower pressure means that the sputtered atomsmay collide with fewer gas molecules so that the PVD collimation isincreased. A secondary electron source (e.g. hollow cathode source)and/or another pumping port in the vicinity of the target may also beadded to the dual collimator to further reduce the minimum sputteringpressure which reduces the likelihood a sputtered atom may strike a gasmolecule. Finally, atoms that experience large angle collisions in thelong-throw collimator are filtered out or stopped by the physicalcollimator so collimation is further increased.

FIG. 2 illustrates an example of a series of process steps that benefitfrom the use of a dual collimator in accordance with the invention. Inparticular, an abutted junction for a magneto-resistive (MR) head may beformed by a lift-off process in which highly collimated sputtered atomsare desirable because the lift-off process will not be clean if a fairlysharp sidewall cannot be formed. In particular, for the abuttedjunction, it is desirable to minimize sidewall coverage—particularlyunder an overhang structure. Any deposition of metal on sidewalls of thestructure is detrimental to pattern fidelity and may result in flapswhich can break free from the structure and contribute to surfaceparticle contamination.

For higher recording densities, track widths become narrower and abuttedjunctions formed using dual collimation allow for narrower track widths.Another application for dual collimation is improved step coverage forliner/barrier deposition in high-aspect-ratio vias/trenches encounteredin ULSI devices, such as semiconductor interconnect structures.Traditionally, either physical or long-throw collimation have been usedbut these techniques are ineffective for aspect ratios exceeding 4:1.

In the magneto-resistive (MR) head process, a release layer 80, an MRmaterial 84, and a resist material 82 are formed on a ceramic substrate.The MR layer is then patterned by the ion milling as shown in FIG. 2.Next, a chromium underlayer 86 and a cobalt-chromium-platinum (CoCrPt)layer 88 are deposited along the entire substrate using a collimateddeposition method. Next, a lead metal layer 90 is deposited along theentire substrate preferably using a dual collimator in accordance withthe invention so that the sidewall deposition of the lead metal isminimized and the central portion may be lifted off without havingpieces of the sputtered material break off because they are attached tothe central portion. Three deposition steps in this process sequence canbe performed using the dual collimation technique of this invention. Anexample of a dual collimator in accordance with the invention will nowbe described.

FIG. 3 is a diagram of an example of the dual collimator 56 inaccordance with the invention. In this example, the collimator may havea target 64 that is 12″ in diameter, a wafer 66 which is 6″ in diameter,and a 12″ distance between the target 64 and a physical collimator 68.The physical collimator 68 may have a 2:1 aspect ratio in this example(i.e., the ratio of the height of the holes in the plate to theirdiameter). As shown, due to the combination of the long-throw collimatorand the physical collimator, only the sputtered atoms traveling in theshaded region may reach point A on the wafer. Therefore, the maximumincident angle is closer to 0° so that more of the sputtered atomsstrike the wafer perpendicular to the surface of the wafer (i.e. morecollimated atoms). Now, various experimental results with the dualcollimator in accordance with the invention will be described.

First, the experimental results for the DC magnetron deposition of Crand CoCrPt layers for an MR head as shown in FIG. 2 using a dualcollimator is described. The Cr and CoCrPt collimation experiments wereperformed on a CVC Connexion-600 platform using one process moduleconfigured for DC magnetron sputter deposition. An apple-shapedmagnetron array for the Cr depositions was equipped with samarium cobalt(SmCo) magnets while the array used for CoCrPt was equipped with higherstrength neodymium iron boron (NdFeB) magnets. The module was configuredwith two collimation sources placed in series: (1) a long-throwcollimator providing an aspect ratio of 1:1 and (2) a honeycomb patternphysical collimator with an aspect ratio of 2:1. The process gas wasinjected into the chamber through a port in the long-throw collimatorcollar midway between the target and the physical collimator. Thisinjection position provides unrestricted gas flow to the plasma whilepossibly allowing a reduced pressure below the physical collimator.

Preliminary experiments were performed to determine the minimum pressurenecessary to generate and sustain a stable plasma. The minimization ofthe process pressure necessary for a plasma allows for an increased meanfree path of the sputtered material (i.e., the sputtered atoms orspecies may strike fewer gas atoms during deposition) which is requiredto maintain a high degree of collimation. For Cr deposition, the stableprocess pressure was determined to be 0.8 mTorr and was limited by thestability of the throttle valve controller. For CoCrPt, the processpressure was maintained at 1.5 mTorr to ensure process stability. Inboth cases, the plasma was ignited at 30 mTorr with a gas burst and thenthe pressure was reduced for the pre-deposition target clean. Followingthe target pre-clean, the shutter was opened with the plasma ignited andthe deposition timer started. The deposition rate and stressmeasurements were performed on 4″ oxide-coated silicon (Si) wafers. Thedemonstration depositions were performed on aluminum oxide titaniumcarbide (AlTiC) pucks with photo-resist patterns and on 6″blanket/patterned oxide-coated Si wafers.

The process recipes used for the collimation experiments and thecorresponding deposition rates and stress values are summarized inTable 1. All samples received a pre-deposition sputter etch (clean) ofthe surface at 400 W in a 6 mTorr argon (Ar) ambient.

TABLE 1 Summary of process parameters for Cr and CoCrPt depositions.Parameter Cr CoCrPt Power (W) 4000 4000 Pressure (mTorr) 0.8 1.5 Bias(W)/(V) 9/80 0/1 Chk. Ht. (in) 1.3 1.3 Flow (sccm) 10 15 Rate (Å/s) 1.82.9 Stress (dynes/cm²) 4.6 × 10⁸ tensile 8.0 × 10⁹ tensile

A three layer stack structure consisting of a 30 Å thick Cr layer, a 350Å thick Co₈₂Cr₆Pt₁₂ layer and a 1150 Å thick Cr layer was deposited.Because only one set of collimators was available, the three layers weredeposited on three sequential days. On day 1, a 50 Å layer of Cr wasdeposited and the samples were stored in the load-lock overnight whilethe chamber was prepared for the CoCrPt depositions. On day 2, 20 Å ofCr was etched from the substrate surface and a 370 Å layer of CoCrPt wasdeposited on top of the Cr and stored in the load-lock overnight. On day3, 20 Å of CoCrPt was removed and 1150 Å of Cr deposited. The etch rateswere determined by measuring the sheet resistance of a film of knownthickness before etching under the conditions described above. After theetch experiment, the sheet resistance was re-measured to determine theamount of material removed. To remove 20 Å of Cr, the etch was performedfor 48 seconds while only 30 seconds were required to remove 20 Å ofCoCrPt.

For uniformity improvement experiments, depositions of both Cr andmolybdenum (Mo) were performed using the dual collimation configuration.For the DC magnetron sputtering apparatus in the experiments, SmComagnets were used to fabricate a variety of magnetron arrays, while aNdFeB magnet array was used during the optimization of the design of thephysical collimator. The module was configured with two collimationsources placed in series as shown in FIG. 3, with a long-throwcollimator providing an aspect ratio of 1:1 and a honeycomb patternphysical collimator with an aspect ratio of 1.5:1. The process gas wasinjected into the chamber through a port in the long-throw collimatormidway between the target and the physical collimator. This injectionport provides unrestricted gas flow to the plasma while possiblyallowing a reduced pressure below the physical collimator.

For evaluating various magnetron designs, the distance from the targetto the physical collimator was set to 12.25″ and the distance from thephysical collimator to the chuck was set at 3.5″. While optimizing thephysical collimator these distances were changed to 10.5″ and 5.25″ byadding a 1.75″ chamber spacer under the physical collimator. Thethickness of the physical collimator is ⅞″. All film depositions wereperformed on 6″ oxide coated Si wafers. The sheet resistance anduniformity (measured at diameters of 6″, 5″, and 4″) were determinedusing a CDE ResMap resistivity probe employing 121, 81, and 49 pointmeasurement templates, respectively. Deposition rates were determinedbased on the measurements of film thickness on 4″ Si wafers withphoto-resist patterns using a Tencor P2 profilometer. Now, the resultsof the experiment are described.

For the dual collimation configuration using a standard magnetron arrayand a physical collimator, the deposition rate was determined to be 28Å/kW/min for Cr and 44 Å/kW/min for CoCrPt with a depositionnon-uniformity of 3.2%, 1σ for both materials. The correspondingresistivities are 22.4 μΩ-cm for a 300 Å Cr layer and 67.4 μΩ-cm for a370 Å CoCrPt layer. In prior work, we measured a deposition rate of 100Å/kW/min for Cr using only the long-throw collimator. The depositionrate measured for this set of experiments is much lower and can beattributed to the additional degree of PVD collimation provided by thephysical collimator.

FIG. 4 is a chart of the amount of sputtering atoms (flux) over variousincident angles to the substrate. A perfectly collimated layer wouldhave all of the atoms at a normal incidence. As shown, with nocollimation, a curve 100 is produced which has a full width half maximum(FWHM) value between a +55° and a −55° incident angle. A long-throwcollimator produces a curve 102 with a FWHM angular value between ±45°incident angle indicating better collimation. In accordance with theinvention, a dual collimator may produce a curve 104 having a FWHM valuebetween ±25° incident angle indicating a better collimation than nocollimator or a long-throw collimator. The fact that the deposition ratewas reduced only by a factor of four suggests that both the long-throwand physical collimators are providing some degree of collimation. Ifthe long-throw collimator was not effective in filtering the flux, alarger reduction would have been measured. Another feature is that inthe dual collimation configuration, the physical collimator blocks onlya small fraction of the flux because most of the flux is filtered by thelong throw collimator. When the physical collimator is used by itself,the physical collimator blocks a large fraction of the incident fluxwhich necessitates frequent cleaning. Thus the dual collimation inaccordance with the invention also increases themean-wafer-between-cleans (MWBC) time since less flux reaches thephysical collimator in the dual collimator. The MWBC may be furtherincreased by improved shield designs in accordance with the invention asdescribed below.

FIG. 5 illustrates a VSM measurement of a 0.25″ square sample of thefinished stack. The sample was cut from a 6″ pilot wafer processed inparallel with the AlTiC pucks. The sample is isotropic and displays acoercivity of 1630 Oe, a squareness of 0.91, and a saturationmagnetization of 0.9 mEMU. The film sheet resistance is 1.58 Ω/sq. witha non-uniformity value of 5.7%, 1σ.

Returning to the MR head process flow as shown in FIG. 2, followingdeposition and removal of the resist, the sidewall angle of the metalunder the overhang was characterized. FIG. 6A is a diagram illustratingproperties which characterize an overhang structure 110. In particular,a sidewall angle, ⊖, of a sidewall 111 is ideally closer to 90°. Anencroachment distance, X, is the distance that the deposited layerextends underneath an overhang 112. A smaller encroachment distance isdesirable. FIG. 6B is a graph generated by an atomic force microscope(AFM) scan of the overhang structure 110 showing the sidewall angle, ⊖,of the sidewall 111. The sidewall angle is a function of type ofcollimation with dual collimation providing the steepest angle as shownin Table 2.

TABLE 2 Collimation Method Sidewall angle ⊖ (deg.) Encroachment × (μm)None 10-12 0.55 Physical 15-17 0.40 Long-throw 17-20 0.35 Dual(invention) 31-36 0.15

FIGS. 7A and 7B are AFM scans of an MR head formed with no collimationand an MR head formed with a dual collimator in accordance with theinvention, respectively. As shown, the MR head formed withnon-collimated deposited atoms has a sidewall angle which issignificantly less than 90° and some encroachment is evident. The MRhead formed with the dual collimator has a sidewall angle closer to 90°and less encroachment. Clearly, dual collimation provides less overlapof the MR sensor. Excessive overlap will result in formation of multipledomains at the edge of the MR sensor leading to instability duringoperation. The reduction in overlap and material deposition under theoverhang is also clear from the FIB-TEM images shown in FIGS. 8a and 8b.

The dual collimation may also improve step coverage. FIG. 9A is an SEMpicture of via holes with a tantalum (Ta) layer deposited using physicalcollimation deposition and FIG. 9B is an SEM picture of via holes with aTa layer deposited using a dual collimator in accordance with theinvention. As shown, the Ta layer formed using a physical collimator hascoverage on the sidewalls but poor bottom coverage whereas the Ta layerdeposited using dual collimation PVD in accordance with the inventionhas uniform sidewalls and better bottom coverage properties.

The deposition rate and uniformity for the dual collimator in accordancewith the invention may also be affected by other factors which are nowdescribed. First, the effects of different magnetron designs isdiscussed. The process recipes used for evaluating magnetron designs andthe corresponding deposition rates are summarized in Table 3 set forthbelow. Different sizes of circular magnet arrays that were tested areshown in FIGS. 10a-10 d including 4″ (12 SmCo magnets), 6″ (24 SmComagnets), 8″ (32 SmCo magnets), and 10″ (40 SmCo magnets) arrays. Eacharray was evaluated for Cr deposition. Prior to the deposition, allsamples were subjected to a pre-deposition sputter etch (clean) of thesurface at 400 W for 60 seconds in a 6 mTorr Ar ambient.

For both the 6″ and 8″ magnetron arrays, the deposition rates weredetermined to be ˜54 Å/kW/min in Ar at 0.8 mTorr with depositionnon-uniformity values of 7.4% (1σ) and 5.2% (1σ), respectively. Thus, asmaller magnetron array may be used in conjunction with a smaller targetto enhance the fraction of the target material that is deposited on thewafer which enhances the effective target utilization. However, at least1.8 mTorr gas pressure was necessary for sustaining a stable plasma withthe 4″ magnetron array. For the 10″ magnetron array, stable plasma couldnot be sustained unless the pressure was increased to 5 mTorr and thepower decreased to 1 kW. In addition, the deposition rate for the 10″array was very low (i.e., approximately 4 Å/kW/min). The results are setforth in Table 3.

TABLE 3 Summary of Process Parameters for Different MagnetronsParameters 4″ 6″ 8″ 10″ Power (W) 2000 2000 2000 1000 Pressure 1.8 0.80.8 5 (mTorr) Bias (W)/(V) 9/80 9/80 9/80 9/80 Chk. Ht. (in) 1.3 1.3 1.31.3 Flow (sccm) 10 10 10 40 Rate (Å/s) 1.8 1.8

These preliminary experiments revealed a deposition non-uniformityof >6% (1σ) on 6″ wafers for dual collimated Cr deposition using thehigh strength magnetron for chuck heights of 1.3″ to 3.5″.

To increase the collimation and deposition uniformity of the dualcollimator in accordance with the invention, the physical collimator'scharacteristics may be modified. In particular, three differentapproaches were used to vary the sputtered atom flux transmissionthrough the physical collimator in order to improve the depositionuniformity: 1) a 4″ diameter piece of aluminum foil with evenly spacedholes was placed over the central area of physical collimator; 2) twopieces of round metal gauze, which were 4 cm and 1.5 cm in diameter,respectively, were stacked over the central area of physical collimator;and 3) the height of the physical collimator at predetermined points wasincreased. For example, the height may be increased by 4 mm in thecenter and the 1st hexagonal ring and by 2 mm for the 2nd hexagonal ringof the physical collimator where the original height of physicalcollimator was 24 mm. The first two approaches altered the collimatorhole size, while the third approach locally modified the collimatorheight.

FIG. 11 is a diagram illustrating an example of a physical collimator120 having a plurality of hexagonally shaped openings. The height of acenter region 122 and a first ring of hexagonal cells 124 is 4 mm higherthan the collimator which may be 24 mm high. A second ring of regions126 may be 2 mm higher than the rest of the collimator. Thus, thecentral portion of the physical collimator is higher than the secondring of regions 126 which is in turn higher than a plurality of outerrings 128 of the physical collimator. Thus, the aspect ratio of thephysical collimator is highest at the center of the physical collimatorand decreases as one moves to the outside edge of the physicalcollimator. Thus, at the inner regions 122, 124 of the physicalcollimator, deposited atoms must be highly collimated to pass throughthe holes due to the higher aspect ratio. Modifying the physicalcollimator height locally (as with the third approach) was preferable toaltering the collimator hole size (approaches 1 and 2) since only asmall modulation in height is necessary, and the hexagonal geometry ofthe collimator is retained.

The process parameters used for the modification of physical collimatorand the deposition rate are summarized in Table 4 set forth below. Ahigh field magnetron equipped with high strength NdFeB magnets was usedfor this investigation. All samples received a pre-deposition sputteretch (clean) of the surface at 400 W for 60 seconds in a 6 mTorr Aratmosphere.

TABLE 4 Process Parameters Parameter Cr Mo Power (W) 4000 4000 Pressure(mTorr) 0.8-5   0.8 Bias (W)/(V) 9/80 9/80 Chuck height (in) 1.3-3.5 1.8Flow (sccm) 10 10 Rate (Å/s) 2.8

With the modified physical collimator, a series of Cr depositions wereperformed at various chuck heights (1.7-2.2″). The corresponding sheetresistance and uniformity values for those depositions are summarized inTable 5 set forth below, and plotted as shown in FIG. 12. The uniformitywas significantly improved, decreasing from 6.3% (1σ) to 1.6% (1σ) on 6″wafers. Corresponding non-uniformity on 5″ and 4″ wafers was ˜1.2% (1σ)at a chuck height of 1.7-1.8″. It is expected that a uniformity of <1.5%(1σ) may be achieved with further fine tuning the height of portions ofthe physical collimator.

TABLE 5 Chuck Ht. R_(s) Uniformity (6″) Uniformity (5″) Uniformity (4″)(inch) (Ω/sq) (%, 1σ) (%, 1σ) (%, 1σ) 1.7 8.763 1.66 1.07 1.23 1.8 8.8491.60 1.21 1.44 1.9 8.457 1.86 1.57 1.83 2.0 9.251 2.03 — — 2.1 8.6862.44 — — 2.2 8.505 2.92 — —

A series of Cr depositions were also performed at various pressuresfollowing modification of the physical collimator. The correspondingsheet resistance and uniformity values are summarized in Table 6 as setforth below. As the deposition pressure increased, both the sheetresistance and non-uniformity increased, from 8.749 Ω/sq and 1.60% (1σ)at 0.8 mTorr to 57.13 Ω/sq and 4.98% (1σ) at 5 mTorr (at the optimizedchuck height of 1.8″). These results are also shown plotted in FIG. 13.

TABLE 6 Pressure R_(s) Uniformity (6″) Uniformity (5″) Uniformity (4″)(mTorr) (Ω/sq) (%, 1σ) (%, 1σ) (%, 1σ) 0.8 8.763 1.60 1.07 1.23 1.09.430 1.69 1.26 1.66 2.0 13.05 2.02 — — 3.0 21.42 3.68 — — 4.0 32.374.54 — — 5.0 57.13 4.98 — —

Further investigation of dual collimated Mo deposition was alsoconducted in order to determine whether the modified physical collimatorwas also suitable for a heavier metal target. The results showed adeposition non-uniformity of 2.3% (1σ) on 6″ wafers although the atomicweight of Mo is about twice that of Cr (96 g/mole for Mo compared to 52g/mole for Cr). This results in higher average kinetic energy andreduced scattering due to the collisions with background gas atoms.

To further understand the invention, several simulations were performed.These simulations were performed using a software application known asSIMBAD (a profile evolution program from the Univ. of AlbertaMicroelectronics Center) to determine the effect of collimation on theFWHM of the sputtered flux incident on the wafer. A schematic of aresist structure (for lift-off patterning) that was used for thesimulation is shown in FIG. 14 and various typical dimensions are shownin Table 7a.

TABLE 7A Pattern Geometry Dimension Value a (μm) 0.04-0.12 b (μm)0.1-0.3 c (μm) 1.2 d (μm) 0.3-0.7 e (μm) 1   Metal (Å)  400-2200

It is desirable is to prevent deposition under the overhang so that theresist lifts off cleanly following sputter deposition. The purpose ofthe simulation was to adjust the collimation of the incoming sputterspecies to match the experimentally observed sidewall angle. Theincoming distribution of sputtered atoms was parameterized as cos^(x)αwhere α is angle of the sputtered flux incident at the wafer. Theparameter x was varied until the sidewall angle that the edge of themetal makes with the horizontal plane matched the experimental resultsdescribed above. As discussed before, the collimation can be quantifiedby the sidewall angle; the greater the collimation, the greater theangle that the edge of the metal makes with the horizontal (see FIG.14). The sidewall angle for various types of collimation (derived fromthe experimental data above) is shown in Table 7b. A stickingcoefficient of 0.9 was assumed for the simulations.

TABLE 7B Effects of Collimation Angle of metal Value No collimation 10°Long-throw collimation 16° Dual collimation 32°

The results of the simulation are shown in FIGS. 15a and 15 b for nocollimation, FIG. 16a and 16 b for long-throw collimation and FIGS. 17aand 17 b for dual collimation in accordance with the invention,respectively. Comparing FIGS. 15a, 16 a and 17 a, the flux distributionfor a dual collimator is more collimated as shown by the narrower peakregion. As shown in FIGS. 15b, 16 b and 17 b, no collimation permitquite a bit of material to be deposited underneath the overhang whilethe dual collimation does not have much material deposited under theoverhang. As can be seen, the abutted junction is best defined for thedual collimation since the FWHM of the sputtered atom distributionincident on the wafer surface is ±25° compared to ±45° for long-throwcollimation and ±55° for no collimation.

For the best performance for an abutted junction, a permanent magnetmust contact the MR sensor only along the beveled surface with minimaloverlap. Any overlap with the MR sensor is not desirable since itaffects the track width and does not provide well defined magneticorientation/biasing. Dual collimation clearly provides a well definedabutted junction with these attributes.

In addition to the above abutted junction simulation, the effect ofcollimation parameters on the incoming flux of atoms at the wafersurface was simulated in order to determine the optimal collimatordimensions. The following geometry, as shown in FIG. 18, was simulated.In this simulation, a target 130 was 12″ in diameter, a wafer 132 was 6″in diameter, a region 134 of the chamber above a physical collimator 136was 12″ high and 19″ diameter, a lower region 138 was 3″ high and thephysical collimator 136 was 1″ tall with a 2:1 aspect ratio.

The nominal operating conditions were a pressure of 1 mTorr, Arsputtering gas, and a Cr target. Uniform, full-face erosion of thetarget was assumed, which is valid for a rotating magnetron design. Thephysical collimator consists of 0.5″ diameter hexagonal holes that are1″ tall. The transmission rate through the collimator was set at 80%(i.e., if all the atoms were traveling normal to the target surface, 80%of the atoms would pass through the collimator). The intent of thesimulation was to determine the angular distribution of the flux ofatoms arriving at the wafer surface as a function of chamber height (h).The nominal chamber height is 12″, but chamber heights of 6″, 9″, 12″and 15″ were evaluated. The angular distribution was computed both atthe center of the wafer and at the edge of the wafer for comparison. TheFWHM of the angular distribution was used as a quantitative measure ofthe degree of collimation.

The following physical phenomena were included in the simulation: 1) 2-Daxisymmetric geometry; 2) cos ⊖ dependence of flux ejected from thetarget; 3) Uniform and full face erosion of the target; 4) Scattering ofatoms through collisions with the background gas; and 5) Physicalblocking of atoms with large angle trajectories by the collimator.Additional parameter values used in the simulation are set forth onTable 8.

TABLE 8 Process Parameters Parameter Value Parameter Value Targetvoltage 400 V Wafer diameter 6″ Cr binding energy 4.1 eV Gas temperature125° C. Cr mass 52 amu Ar mass 37.55 amu Chamber radius 9.5″ Pressure 1mTorr Throw distance 10·19″ Collimator 0.5″ × 1″

The full width half maximum (FWHM) of the angular distribution of theatomic flux arriving at the wafer surface as it depends of the height ofthe long-throw collimator are shown in FIG. 19a and the angulardistribution for a 12″ tall collimator is shown in FIG. 19b. The FWHM isonly slightly dependent on the height of the long-throw collimator.However, the relative deposition rate and relative lifetime of thephysical collimator is very dependent on the height of the long-throwcollimator as shown in FIG. 20. The relative lifetime is related to theratios of the deposition rate on the physical collimator and the wafer.The lower the ratio, the longer the lifetime of the physical collimator.These simulations indicate that a long-throw collimator height of 6″-9″is optimal for this application.

The basic configuration of the dual collimation apparatus in accordancewith the invention has now been described. There are a number ofenhancements which may improve the collimation or the depositionuniformity of the dual collimator. For example, more than one physicalcollimator may be used to create a configuration in which a physicalcollimator is located at both ends of the long-throw collimator. Inaddition to further improve collimation, such a dual physical collimatorconfiguration can provide additional advantages such as separating theprocess space around the target from the process space around the wafer.If the long-throw collimator is equipped with a pumping port and a gasinjection ring is installed around the target, an inert gas can beinjected through the gas injection ring around the target, while areactive gas may be injected in the vicinity of the wafer. This wouldpermit a chemical reaction to proceed at the wafer surface withoutpoisoning the target. In addition, an electron source (e.g., ahollow-cathode source) may be installed in the long-throw collimator toallow for low pressure processing near the wafer which is desirable toreduce the probability of scattering collisions within the long-throwcollimator. Also, the optimal collimator aspect ratio depends on theapplication, and a lower collimation can be traded off for improvedproductivity.

While the dual collimation system has been demonstrated for DC magnetronsputtering, it may also be used in conjunction with other sputteringtechniques such as RF diode sputtering, ionized physical-vapordeposition (PVD) and ion beam deposition. For ionized PVD, the physicalcollimator may also be biased to preferentially extract directionalionized atoms.

One limitation of a sputter deposition apparatus is the flaking ofdeposited material from the walls of the long-throw collimator. This isespecially acute in the lower portion of the long-throw collimator wherethe incoming flux is incident at glancing angles to the surface of thewalls of the long-throw collimator. Any flux at large incident anglesusually results in films with high tensile stress that are prone todelamination/flaking. The delamination/flaking of the film on the shieldmay corrupt the film deposited on the wafer. Several potential solutionsto this problem include: 1) the use of ‘chevron’ shaped or conicalshields that reduce incidence angles of the incoming flux as describedbelow; 2) aperture shields to block the large angle flux from reachingthe walls of the physical collimator, and 3) lining the inner surface ofthe long throw collimator with shields that have special coatings (e.g.,flame sprayed Al) that promote adhesion.

FIGS. 21 and 22 are diagrams illustrating several embodiments of ashield 140 that decrease incident angles of incoming flux. Inparticular, as shown in FIG. 21, the shield 140 may include inwardlyslanted sidewalls 142, 144 and a plurality of rings 146, substantiallyperpendicular to the sidewalls. As atoms are released from a target 148,they may strike the shield 140 at closer to a 90° incident angle due tothe slanted shield design so that the film produced on the shield isless likely to delaminate or flake. In addition, at a shelf 150 formedby the rings 146 and the slanted sidewalls 142, 144, any material whichdelaminates or flakes off may be caught by the shelf instead of cloggingup the holes in a physical collimator 152. Therefore, themean-time-between-cleans of the physical collimator is increasedresulting in improved PVD productivity.

FIG. 22 is another embodiment of the shield 140 that may have acylindrical main i shield 160, a plurality of circular arms 164 whichintersect the cylindrical shield at a predetermined angle, and an outerbent portion 166 located at the end of the circular arms. As describedabove, this shield reduces the incident angle of atoms deposited on theshield to reduce delamination and may trap any delaminated material in ashelf 168 formed by the end portion and a circular arm.

The advantages of dual collimation for improved pattern definition havebeen demonstrated. This technique is especially suitable for patterningusing both lift-off structures and shadow masks. Since collimationresults in a directional flux that is similar at various points on thesubstrate, this technique can be used to control filmtexture/orientation and stress. It improves bottom coverage which is notonly beneficial for liners or barriers for vias or trenches,respectively, but also for a trench/via fill. Finally, the intrinsicallylow deposition rate leads to other advantages such as good control atlow deposition rates and reduced deposition process-induced damage ofsensitive substrates.

In summary, a dual collimation method in accordance with the inventioncombines a long-throw collimator is combined with a physical collimatorhas been developed for improved step coverage for barriers/liners invias/trenches, respectively, and reduced encroachment in lift-offstructures for abutted junctions. The physical collimator providesadditional filtering of the sputtered flux enhancing the collimation.Since the physical collimator blocks only a small fraction of theincoming flux, physical collimator lifetime is increased. By operatingat low pressures (<2 mTorr) the probability of scattering due tocollisions with background gas atoms is minimized thereby preservingcollimation. The experimental data shows that bottom coverage for a 3:1aspect ratio (A.R.) via improves from 30% (for physical collimation) to50% for dual collimation while sidewall coverage is not significantlyaffected. Compared to the case of no collimation, dual collimation alsoresults in a 3 times reduction in encroachment for lift-off structures.The sidewall angle of the metal deposited on lift-off structures withrespect to the horizontal plane increases from 10° for no collimation to16° for long-throw collimation and 32° for dual collimation. Simulationsusing SIMBAD indicate that the FWHM (full-width-half-maximum) of thesputtered flux incident on the wafer decreases from ±55° for nocollimation to ±45° for long-throw collimation and ±25° for dualcollimation. Simulations indicate that the FWHM of the sputtered flux isonly weakly dependent on the height of the long-throw collimator. Thelifetime of the physical collimator (when expressed in terms of thetotal deposition on the substrate) is invariant for collimators that are6″-15″ tall, but the deposition rate is inversely proportional to theheight of the long-throw collimator.

The deposition rate decreased from 100 Å/kW/min (with long-throwcollimator only) to approximately 28 Å/kW/min for a dual collimator.This decrease in rate can be attributed to the increased degree ofcollimation. A Cr(30 Å)/Co₈₂Cr₆Pt₁₂ (350 Å)/Cr (1150 Å) stack processedusing dual collimation shows excellent magnetic properties with acoercivity of 1630 Oe and a squareness of 0.91. Dual collimation is anattractive approach for abutted junction formation and barrier/linerdeposition in high aspect ratio vias/trenches.

While the foregoing has been with reference to a particular embodimentof the invention, it will be appreciated by those skilled in the artthat changes in this embodiment may be made without departing from theprinciples and spirit of the invention, the scope of which is defined bythe appended claims.

What is claimed is:
 1. A physical-vapor deposition apparatus fordepositing material from a target onto a substrate, the apparatuscomprising: a deposition chamber; a target assembly disposed at one endof the chamber and holding the target from which sputter depositionparticles are generated; a substrate holder housed within the chamber ata predetermined distance from the target assembly and substantiallyfacing the target assembly; a physical collimator between the targetassembly and the substrate holder for spatially filtering of the angulardistribution of sputter deposition particles impinging on the substrate;and a long-throw collimator extending between the target assembly andthe physical collimator, the long-throw collimator being adapted toprevent sputter deposition particles falling outside a predeterminedangular distribution cone from striking the physical collimator, andacting in combination with the physical collimator to further spatiallyfilter the angular distribution of sputter deposition particlesimpinging on the substrate.
 2. The apparatus of claim 1, furthercomprising an ionizing source collimator which is disposed within saiddeposition chamber.
 3. The apparatus of claim 1 further comprising asecond physical collimator.
 4. The apparatus of claim 1, wherein thedeposition apparatus comprises one of a DC and a pulsed DC magnetronsputtering apparatus.
 5. The apparatus of claim 4, wherein said DCmagnetron sputtering apparatus further comprises a rotating magnetronoptimized for a predetermined level of target utilization.
 6. Theapparatus of claim 1, wherein the deposition apparatus comprises anionizing physical-vapor deposition apparatus.
 7. The apparatus claim 1,wherein the deposition apparatus comprises one of an RF diode and an RFmagnetron sputtering apparatus.
 8. The apparatus of claim 1, wherein thedeposition apparatus comprises an ion beam deposition apparatus.
 9. Theapparatus of claim 1, wherein the physical collimator further comprisesa plate located between the target and the substrate, the particlespassing through apertures in the plate.
 10. The apparatus of claim 9,wherein said plate further comprises a central portion having apertureswith a predetermined first aspect ratio and an outer portion havingapertures with a predetermined second aspect ratio.
 11. The apparatus ofclaim 1 further comprising a removable shield for protecting thedeposition chamber from accumulated sputter deposition particles. 12.The apparatus of claim 11, wherein the shield comprises a shield walland one or more arm portions extending inward from the shield wall at apredetermined angle so that deposition particles which strike the shieldwall and arm portions do not result in particulate contamination of thesubstrate.
 13. The apparatus of claim 12, wherein the shield wall isslanted towards the center of the deposition chamber by making theshield aperture larger near the target assembly and smaller near thesubstrate and wherein the arm portions are at a right angle to theshield wall.
 14. The apparatus of claim 12, wherein the arm portions ofthe shield further comprise a first arm portion extending from theshield wall and a second arm portion extending from the first armportion at a predetermined angle.
 15. The apparatus of claim 1 furthercomprising a gas injection port between the target assembly and thephysical collimator.
 16. The apparatus of claim 1, wherein thelong-throw collimator comprises a pumping port for injecting gas intothe deposition chamber.
 17. The apparatus of claim 1 further comprisinga gas injection ring around said target for injecting gas into thedeposition chamber.
 18. The apparatus of claim 1, wherein said targetassembly comprises a hollow-cathode target assembly.
 19. The apparatusof claim 1, wherein said physical collimator comprises a perforatedplate having a predetermined pattern of holes in the plate.
 20. Theapparatus of claim 19, wherein said physical collimator furthercomprises a predetermined pattern of circular holes in the plate. 21.The apparatus of claim 19, wherein said physical collimator furthercomprises a predetermined pattern of hexagonal holes in the plate. 22.The apparatus of claim 1, wherein said substrate holder is positionedbeneath said target assembly for sputter-down deposition.
 23. Theapparatus of claim 1, wherein said substrate holder is positioned abovesaid target assembly for sputter-up deposition.
 24. The apparatus ofclaim 1, wherein said substrate comprises a semiconductor integratedcircuit substrate for forming interconnect structures on thesemiconductor integrated circuit substrate.
 25. The apparatus of claim1, wherein said substrate comprises a substrate for forming magneticthin-film heads.
 26. The apparatus of claim 1, wherein the long throwcollimator comprises at least sidewall of the deposition chamber. 27.The apparatus of claim 26, wherein the at least one sidewall comprises apair of sidewalls.
 28. The apparatus of claim 26, wherein the at leastone sidewall comprises a cylindrical sidewall.